Obesity, closely linked to several health problems, including cancer, has reached epidemic levels in the U.S. The highest rates are seen in minority populations, including Native Hawaiians and other Pacific Islanders. Obese children and adolescents are more likely to be obese into adulthood, and obesity in adults is difficult to treat. Interventions in childhood should help prevent adult obesity, but few schools have time to provide regular physical education. Can schools incorporate a 15-20-minute exercise program that maximizes oxygen intake capacity (VO2 max), and can this help children achieve healthy body weights? This study proposes to: 1) conduct a preliminary field test of effectiveness a 15-20-minute physical activity program 2) determine the feasibility of inserting it into the daily routine of elementary school classrooms Two schools in the Kahuku Elementary School complex on O'ahu, in which half of children are Native Hawaiian or other Pacific Islander, have agreed to be involved in the study. Each school enroll enrolls about 500 students in grades 1-6. In each school, classrooms at each grade level-1st through 6th-will be randomized into treatment and control classrooms. Treatment classrooms will receive the intervention-the 15-20-minute physical activity program 4 days a week, led by college seniors majoring in physical education at a local university. Control classrooms will follow their usual routine. Both schools will receive an honorarium, and control classrooms will receive intervention materials and training after the study is completed. Pre- and post-test measures will be taken of BMI, hip and waist circumferences, skin folds, and direct body composition using the BOD POD of students in treatment and control classrooms. Daily records of participation by students in treatment classrooms will be kept to ascertain their engagement. Feasibility questionnaires will be completed by students, classroom teachers, principals, and school district officials in the middle and at the end of school year. These data will inform a future randomized control trial of the intervention in a much larger sample of schools. [unreadable] [unreadable] [unreadable]